Coaxial line coupling and partition device



Nov. 24, 1964 J. R. BIRD ETAL 3,158,823

COAXIAL. LINE COUPLING AND PARTITION DEVICE Original Filed Oct. 4, 19542 Sheets-Sheet 1 INVENTORS. James E. Bird Biossg 0. Freder/to BY HerbertH. Heller Nov. 24, 1964 J. R. BIRD ETAL COAXIAL LINE COUPLING ANDPARTITION DEVICE Original Filed Oct. 4, 1954 2 Sheets-Sheet 2 INVENTOR.James E 501/, fiiossy 0. Ereder/to. BY Herberl H. Heifer 309M, M bvw,

ATTORNEY-5.

United States Patent 3,158,323 CUAXHAL MINE QQUPLENG AND PARTETEGNDEVTCIE .latnes R. Bird, (Chagrin Falls, Blossy l). Frederiee,Cieveland, and Herbert H. Heiler, (Ilevelaud Heights, Shin, assigners toBird Electronic Corporation, Solon, Ulric, a corporation of @hioOriginal application Oct. 4, i954, tier. No. 46%,(342, now Patent No.2,958,830, dated Nov. 1, 196th. Divided and this application 0st. 7,1959, $621. No. 844,933 18 Ciaims. (61. 333-22) This invention relatesto connecting and partitioning structures useful, for example, inresistive terminations commonly known as dummy loads for high frequencycoaxial lines. A load customarily is designed for use with a coaxialline of specific impedance and preferably is arranged to have an inputimpedance which, over a large range of frequencies, is equal to thecharacteristic impedanceof such line. Reference is made to copendingapplication Serial No. 460,042 filed October 4, 1954, now Patent2,958,830 dated November 1, 1960 for Coaxial Line Load Device, of whichthis is a division. Such a load may comprise an attenuating line sectionincluding an outer sleeve conductor tapered inwardly to its rear end andan inner conductor coaxially mounted within the sleeve and joinedthereto at its rear end. The inner conductor is resistive in character,may be in the form of a thin resistive coating on a ceramic core. Theload or attenuating line section is enclosed in a suitable housingfilled with a liquid dielectric and the tapered outer conductor isperforated or slotted to allow the liquid dielectric, serving also as acoolant, to be in continuous contact or heat exchanging relation withthe inner conductor. The housing containing the bath of liquiddielectric may be cooled by radiant or convective loss of heat to theatmosphere, or, where high power absorption and dissipation is desired,by a circulated refrigerant.

The principal object of the invention is to provide a fluid tightinsulating coupling or connection for very high frequency equipmentdisposed within a housing containing fluid whereby connection may bemade to an external coaxial line with low losses and with littledisturbance of the line characteristics and in a manner precluding lossof fluid from the housing.

In accordance with the invention, the tapered attenuating line sectionis immersed in a liquid dielectric coolant contained in a metal housingso shaped as to promote improved convective flow of the coolant. Theattenuating line section is projected into the housing interior throughan opening adjacent the bottom of one end wall of the housing and issupported by such housing wall. Thus the line section is located closeto the bottom wall of the housing and with its axis substantiallyparallel thereto. The attenuating line section is sealed into thehousingthrough a bush or washer made of a low loss dielectric orinsulating material such as polytetraiiuoroethylone or a compound knowncommercially as Teflon. The seals to the washer are made of narrowsections with undercut sealing surfaces whereby to achieve both amechanical interlock and a tight seal, despite the cold-iiowcharacteristics of the material of the insulator.

At the input end of the line section is an annular conducting ring whichis a part of or is sealed to the container and is in contact with theouter conductor or a fitting coupled to it, and an annular insulatingbush which is Within the ring and around the inner conductor or afitting coupled to it, the bush being sealed and mechanically heldagainst axial movement in relation to the inner conductor or fitting andthe annular conducting ring, whereby the ring and bush comprise aclosure for the container opening. The device includes means forcoupling the attenuating unit to a coaxial line of which the outerconductor can make contact with the annular conducting ring or a fittingcoupled to it and the inner conductor can make contact with the innerconductor of the unit or a fitting coupled to it.

The annular conducting ring may have a recess for the accommodation ofone end of the outer conductor of a coaxial line, or a member secured toit, while the insulator or bush may be sealed around a fitting coupledto the inner conductor of the unit which fitting comprises a standardplug or socket fitting for connection to the inner conductor of acoaxial line.

For further objects and advantages and for a better understanding of theinvention, attention is now directed to an illustrative embodimentrepresenting the best known mode of practicing the invention, as setforth in the following description and as shown in the accompanyingdrawings forming a part of this specification. The features believed tobe novel will be more particularly pointed out in the appended claims.

in the drawings:

FIGURE 1 is an elevation partly in section of an attenuator in the formof a refiectionless termination unit connected to a coaxial line througha coupling embodying the invention;

FIGURE 2 is a detail partly in section of a part of FIGURE 1 to a largerscale, and

FIG. 3 is a fragmentary enlargement of a portion of FIG. 2 showing theinterlocking of the inner and outer peripheries of the insulatingpartition with the inner and outer conductors of a coaxial line system.

Referring to the drawings, there is shown a load device 1 comprising agenerally rectangular housing 2 which serves. as a reservoir or tank forliquid dielectric 3 in which an attenuating line section 4 of thetapered horn type is immersed. The liquid dielectric coolant may be anysuitable liquid such as that available commercially as Dowtherm A. Thehousing may be made of sheet material such as steel, copper, brass,aluminum or the like. Material of good heat conductivity is desirableand in general brass or copper are preferred because of the case ofsoldering and brazing thereto. The housing may be formed of a sheet ofbrass bent with corners to form main side walls and top and bottom wallsabutted edges being welded in a medial seam in the center of the topwall. End walls 11, 12 are fastened by welding in the corners to make afluid-tight enclosure.

The attenuating line section 4 is accommodated in the lower part of thehousing close to the bottom wall and with its axis substantiallyparallel thereto. The attenuating line section comprises a hollow hornor shell 16 which is of tubular form tapering inwardly to its rear end17. This horn surrounds the inner or resistive conductor 18 in coaxialrelation and is preferably tapered exponentially. The inner conductormay comprise a ceramic tube 1% coated with a layer of a resistivecoating 21 sufiiciently thin to eliminate skin effect in relation tocurrents flowing thereto throughout the range of frequencies for whichthe device is designed. The coating 21 may be in the form of carbon,tungsten, platinum or other metal applied by vacuum vaporization,sputtering, painting in colloid dispersion, electrolytic deposition, orother known methods. The outer tapered conductor 16 is perforated asindicated at 22 to allow the circulation of the liquid dielectric 3therethrough; these perforations may be in the form of longitudinalslots, preferably all along the topsurface but only adjacent the smallend in the bottom surface of the horn shaped conductor.

The outer tapered conductor 16 is formed at'its large diameter end withan integral cylindrical portion 10 fastened peripherally to a mountingring 23 over which it is telescoped and which may be made of brass orother relatively soft metal. The fastening may be by soldering or, ifdesired, by mechanical means such as screws placed around the peripheryof the ring. The ring 23 has a rearwardly inclined outer flange 24 atits forward end, this flange being juxtaposed to a forwardly inclinedoutwardly directed radial flange 25 at the forward end of a fasteningring 26. The fastening ring 2:: is externally milled or otherwise cutaway at its inner end to obtain a squared or other non-circular crosssection received matingly and non-rotatively within the matching openingin the upright front wall 11 of the housing. The milling also provides aradial shoulder 27 on the mounting ring which is disposed flatwiseagainst the outside of the housing and is fastened hermetically thereto,preferably by welding or brazing as indicated at 2.8. The milling orcutting away of the inner end of the mounting ring 26 atcircumferentially spaced regions to provide the noncircular shapementioned results in a plurality of circumferentially spaced arcuatesegments 26a which are integral with the body of the mounting ring,project through the housing opening into the housing interior andembrace the cylindrical portion ill of the conductor 16. In theembodiment of the invention presently contemplated there are four of thesegments 26a, two of them being shown in broken lines in FIG. 2. Thesesegments guide the attenuating line section in assembly and support itover a substantial portion of its length to prevent Wobbling of the linein the housing. The body portion of the mounting ring 23 makes a snugsliding fit within the embracing fastening ring 26 and the two are heldtogether by means of a constricting clamping ring 29. The clamping ringis V-shaped in cross section to engage the inclined radial flangeportions 24 and 25 and draw them together. An ring 31 made of softresilient compressible material, not affected by the dielectric fluidwithin the housing, for instance, a rubber-like sealing gasket material,is located between the flange portions 24 and 25. As the clamping ringis tightened circumferentially as by means of screw 32 (FIG. 1), the C;ring washer is compressed and a hermetic seal is achieved.

The outer tapered conductor is and the inner conductor 13 are located inspaced relation at their front end by means of an insulating washer 33made of a low loss dielectric material such as the compoundpolytetrafluoroethylene known commercially as Teflon. The rear outeredge of the spacer 33 is circumferentially rabbeted at 34 to provide ashoulder 33a, which shoulder abuts against face 30 of an inwardlydirected thin shallow flange 35 on the rear end of the mounting ring 23.The mating face 30 of the circumferential flange 35 and the radialshoulder 33a of the insulator 33 or one of them, are inclined slightlyoff the radial in the direction obtaining an undercutting of theshoulder on the partition washer 33 in order to produce a locking effectwhen the insulator is squeezed axially in the manner now to bedescribed.

The structure of the outer conductor for coupling the load device to theend of a transmission line comprises a tubular cylindrical member orportion 35 having at its outer or free end the usual very high frequencybolting flange 37, an intermediate branch line coupling member orportion 38 in the form of a cylindrical tube and a thermal insulatingmember or portion 39 also in the form of a cylindrical tube. The innerend of the cylindrical tube member 39 is provided with a contact ring 41preferably made of brass and brazed thereto. The ring 41 is rabbetedinternally to receive the end of the tube member 39 in a sliding fit inassembly, the abutment of the tube against the bottom of the rabbetserving to locate the tube in predetermined position in the ring. Theforward or outer end of the mounting ring 2-3 is counterbored andinternally threaded to receive a spanner type ring screw 42 provided atits inner end with an internal circumferential rabbet in which isaccommodated a split Washer or ring spacer 43, preferably made of hardmetal as steel. The internal diameter of the ring 42 is greater than theexternal diameter of the thin thermal barrier member 39 in the provisionof an annular clearance 5t) therebetween. When the ring screw 42 istightenec, the spacer ring 43 is forced axially against radial end faceit? of the contact ring 41 which, being fast to the external conductorof the coupling structure locks the line in position. Inner end face 6of the contact ring 41 engages the circumferentially extending outeredge portion of the insulating washer 33 and causes outer periphery 4-4of the partition washer to be squeezed between the inward flange 35 onthe mounting ring 23 and the rear or inner face dd of the contact ring.The end face till is chamfered or inclined oppositely to the inclinedface of the mounting ring flange 35. The partition washer is formed onits outer face 26 and at the juncture of the surfaces defining therabbet 34 with grooves 45 extending circumferentially about thepartition washer and located in underlying relation to the edge cornersof the inclined faces on the flange 35 and the ring end 60.

' Thus the peripheral portion 44 of the partition Washer locatedradially outwardly of or beyond the stress relieving break grooves 45 isnot only squeezed but, is also locked in dovetail fashion so that afluid tight seal is maintained notwithstanding the cold-flowcharacteristics of the material of which the dielectric partition washeror spacer 33 is composed.

The inner conductive structure which connects to the resistive conductor13 is sealed through the insulating partition 33 in the followingfashion. The end of the ceramic core i9 is formed with a reduceddiameter portion 46 and a thin conductive band of plated-on metal suchas silver is applied over the end portion of the resistive coating illand extends over the reduced diameter portion 46. The rear end of acircular sectional conductive plug 47, which may be made of brass, as byturning in a lathe, is formed with a tubular end extension 48 which isreceived telescopically and makes a snug fit over the reduced diameterportion 46 of the inner conductor, the overlapping portions beingsecured together by a conductive cement. Further to assure goodelectrical conductivity at the joint, a band of solder 49 is placed tooverlap tubular extension it; and the plated-on metal contact band ofthe inner conductor 18. The diameter of the plug 47 is the same as thatof the inner conductor 13 whereby to effect a smooth unbroken surfacebetween the parts that constitute the inner conductor of the attenuatingline section. The plug 47 is provided with an external undercut orinclined circumferential shoulder 51. This shoulder is formed bymachining a reduced diameter portion on the plug, by providing a flange,or, as shown, by both a reduced diameter portion and a shallow radialflange. inclined end face 52 of an external mounting cap or ring 53cooperates with the plug shoulder 51 to compress axially an internalradially projecting and circumferentially continuous lip portion 54 or"the insulating spacer or partition 33. The parts are drawn togetheraxially by tightening bolt 55 which passes through a central opening inthe cap 53 and is threaded axially into the end of the plug 4"]. Thisend of the plug is reduced in diameter to provide a pilot 66 which isreceived telescopically within a socket 6'7 drilled into the cap 53,thereby establishing axial alignment of the parts. The socketed end ofthe cap has a reduced diameter end received snugly and locatingly withinthe counterbore in the partition member 33 which is adjacent the annularlip 54 and a deformable Teflon washer or ring 7% embraces the cap and isconfined between the front face 29 of the partition 33 and annularshoulder '71 on the cap 5'3. The internal annular lip 54 is formed withundercut and circumferentially grooved side walls whereby to relieve thestrain in the material when the lip is under axial compression betweenthe inclined annular compression surfaces of the shoulder 51 and the capend face 52. The undercut side walls and the circumferential grooves areindicated in FIG. 3 at 68 and 69, respectively. The lip 54 thus issqueezed in dovetail fashion whereby to provide a locking effect. Thisresults in a hermetical seal which is long-lasting in spite of thecold-flowcharacteristics of the insulating material.

The intermediate portion 39 of the outer conductor is made of materialof relatively low thermal conductivity, such as stainless steel of thetype, say, AISl type 302, and is relatively thin or shell-like in crosssection. By reason of its high strength the 18% chromium, 8% nickel,iron alloy comprising the conductor portion 39 can be made extremelythin, of the order, say, of about .025 inch to about .060 inch at adiameter of 3 inches. Shown is nominal 18 gauge tube about .048 inchthick. The tubular outer member comprising the coupling line section 38has internally rabbeted ends providing short cylindrical sockets orundercuts 56 and 57 which receive the ends of the tubular outer memberscomprising conductor sections 39 and 36 respectively. The overlappingportions of the members are fastened together by suitable means such asbrazing and there is thus provided a smooth unbroken interior surface ofuniform diameter whereby to maintain the characteristic impedanceunchanged throughout the coupling structure.

The outer conductor tube 38 of the branch coupling line section isprovided with a detector mounting block 53 secured as by screws andbrazing. The mounting block 53 is formed with a cylindrical socket thatopens through a mating aperture in the outer conductor of the line so asto provide access to the annular dielectric space surrounding the centerconductor. The mounting block 53 is adapted to receive a suitablevoltage or other detecting or coupling device $4 for sampling the linevoltage or energy at the input end of the attenuating line section loaddevice. Electrical connections to the components of the pickup are madeinside the mounting block 58, the leads being brought out through theside of the blockto a center terminal 85 and a threaded outer terminalboss 86 to which a galvanorneter or other suitable indicator (not shown)may be connected as by means of a coaxial cable having an appropriateend fitting for attachment to the boss 86.

Inner conductor 59 of the coupling line section is in the form of acylindrical brass or other resilient metal tube. At its inner end thistube is formed with axial slots 88 in the provision of a multiplicity ofaxially directed fingers 39 that resiliently embrace the tapered headend of the mounting cap 53. Desirably the inner end of the conductortube 59 is bored or internally relieved to reduce the thickness of thespring contact fingers 89. At its outer end the inner conductor tube 59is supported on the large diameter end of a stepped plug 61 having areduced or small diameter portion received through and supported in thecenter hole of a circular insulating disc 62 of polytetrafiuoroethyleneor similar plastic material. The end of the conductor tube 5% which isreceived over the large diameter inner end of the plug 61 iscounterbored in the provision of a circumferentially extending locatingshoulder 90 which abuts the end of the plug 61 about the periphery ofthe latter and insures that in assembly the outer end of the conductortube 59 is flush with circular plug shoulder 91 defining the stepbetween the large and small diameter portions of the plug 61. Interposedbetween the shoulder 91 and the inside face 92 of the insulating andsupporting disc 62 is a plastic insulating ring 93, which may also beformed of polytetrafluoroethylene or the like. Both the insulating ring93 and a similar ring 94 disposed against outside face 95 of the disc 62are of the same external diameter as the inner conductor tube 59 toobtain the desired electrical characteristics in the transmission linein view of the stepped construction and the change in dielectric fromair to solid plastic insulation andback to air, involving as it doesattendant changes in dielectric constant. To hold the insulating andsupporting disc 62 and the insulating rings 93 and 94 in assembledrelation on the reduced diameter portion of the plug 61, a circularmetal cap 64 is held against the outer end of the plug as by a stud 65that extends through a center bore hole in the cap and is threaded intoan axially extending tapped hole in the plug 61. Desirably a shallowaxial counterbore is formed in the cap 64 about the stud hole in theprovision of an annular socket 96 that receives snugly an axiallydirected pilot extension on the outer end of the plug 61 to locate theparts in predetermined coaxial relation in assembly.

Suitable provision is made for attachment of the coupling line sectionto the end of a coaxial electrical transmission line. coupling lineassembly projects axially beyond the supporting insulating disc 62 andsuch projecting or outer end is bored or otherwise relieved internallyat 57 to receive one end of the outer tubular conductor 36 of thestandard line coupling device. The tubular metal tube 36 is brazed orotherwise secured in the relieved end 57 of the tubular conductorportion 38 and the outer end of the conductor tube 36 carries or issecured in attaching ring 37 of a conventional union.

The inner conductor of the coupling line assembly includes a tubularconductor hail of brass or similar resilient metal having axial slots inits inner end portion. in the provision of resilient fingers 9% thatslide over and yieldingly embracethe tapered periphery of the cap 64. inthis respect the connection of the inner tubular conductor 98 to the cap64 is similar to the connection of the tubular inner conductor 59 of thebranch coupling line section to the cap '33. The fingers 89 of theconductor 5% and the fingers 99 of the conductor 98 are locatinglyabutted axially against the insulating plastic washers '70 and 94,respectively. By reason of the frustoconical or tapered shape of thecaps 53 and 64 the electrical connections between the fingers and thecaps are effected adjacent the axially directed circular radial faces ofthe caps which define the steps to the reduced diameter portions of thecenter conductor extending through the corresponding insulatingpartitions. Furthermore, the tapered or frustoconioal shape of the caps53 and 64 facilitates assembly, in that the ends of the center conductortubes 59 and 98 are easily located over the smaller ends of the caps andthen slid axially into place with attendant slight radial distention ofthe resilient fingers 89 and 99.

In the case of one of the conductor end caps, here the cap 64, provisionis made for piloting into place the tubular conductor that is to bereceived over the cap. This supplemental pilot means takes the form of ametal tube 100 that is secured in endwise relation against the outerface of the cap and in coaxial relation thereto. The pilot tube 100 hasan outer diameter preferably less than the internal diameter of theinner conductor tube 93, providing an annular clearance 10]. between thetubes so that the fingered end of the conductor tube Q8 is readilydisposed over the pilot tube 100 during the initial stage of theassembly. The connections from the main transmission line to the presentload device are thus made by bolting the end flange 37 of the couplingassembly outer conductor 36 to a similar mating union flange (not shown)on the transmission line outer conductor. The end of the inner conductorof the main line is simultaneously connected as by a suitable bulletconnector (not shown) to the inner conductor tube 98.

As a precaution against overloading there is'provided a thermocouple,unit immersed in the liquid dielectric coolant 3 and connected to aconventional electrical safety cut out switch, not shown. The thermalunit is located Within a blind tube 75 which is fastened to a threadedbushing orplug '76 threaded into a ring 78 welded to the front housingwall 11. Lead wires 77 to the thermocouple extend to the safety deviceor, if desired to an indicating meter.

The unit is filled with the liquid dielectric coolant through a bushing'79 in the top wall of the housing. The bushing is internally threadedto receive a plug 81 and The outer tubular conductor 38 of the' the plugin turn is provided With a suitable safety vent screw.

The dielectric fluid within the housing is preferably one having a lowdielectric constant, dielectric constants of the order of about threeand below being satisfactory. It is preferable not to use dielectricshaving constants above five because of the relatively large physicalsize of the outer conductor which would then be required in order toachieve the desired characteristic impedance equal to that of thetransmission line. It is also desirable to use a fluid dielectric havingsubstantially the same dielectric constant as the insulating partition33 in order to avoid the reflective effect of a sudden change indielectric characteristics. For an insulator 33 made of a compound knowncormnercially as Teflon having a dielectric constant of the order ofabout 2.05, suitable liquid dielectrics are an eutectic mixture ofdiphenyl and diphenyl-oxide sold commercially as Dowtherm A and commonmineral oil such as that sold commercially for medicinal purposes asNujol having a dielectric constant of about 2.15. These liquids functioneffectively as coolants by reason of their relatively high specific heatcapacity and low viscosity which facilitate convective flow through thehousing and thereby insure rapid removal of heat from the innerconductor.

While a certain specific embodiment of the invention has beenillustrated and described in detail, the same is intended asillustrative and not as limitative of the invention. The specific sizeand portions of the parts may be varied considerably without departingfrom the invention and it is accordingly int nded, in the appendedclaims to cover any such modifications coming within the true scope ofthe invention.

What we claim and desire to secure by Letters Patent of the UnitedStates is:

1. A junction for joining coaxial line sections each of which comprisesan inner and a tubular outer conductor, said junction comprising anannular outer connector for extending between and electricallyconnecting the outer conductors of the line sections, an in connectorfor extending between and electrically connecting the inner conductorsof the line sections, insulating means surrounding the inner connectorand supporting it coaxially within the outer connector, and means havinga surface inclined to the axis of the connectors providing a dovetailannular interlock between the insulating means and one of theconnectors, said inclined surface engaging the insulating means over arelatively small fractional portion only of the radifl extent of theinsulating means.

2. A junction for joining coaxial line sections each of which comprisesan inner and a tubular outer conductor, said junction comprising anannular outer connector for extending between and electricallyconnecting the outer conductors of the line sections, an inner connectorfor extending between and electrically connecting the inner conductorsof the line sections, an insulator surrounding the inner connector andsupporting it coaxially within the outer connector, and means providingan interlock between the insulator and one of the connectors, the oneconnector including telescoping elements one of which is formed with acylindrical locating surface and the other of which has acircumferential shoulder, the insulator having a cylindrical surfacereceivable in sliding relation against the locating cylindrical surfaceof the one element, the insulator having adjacent its said cylindricalsurface a surface of revolution disposed in concentric relation to theother of the telescoping elements and of different diameter than theinsulator cylindrical surface, the one element having an end facedisposed in confronting relation to the shoulder on the other element,and means operative progressively to draw the elements axially togetherto clamp a portion of the insulator between the end face and theshoulder.

3. In an electrical high frequency device of the type comprising housingmeans formed with an opening and til containing liquid dielectriccoolant and a coaxial line in the housing means and immersed in theliquid,

said line comprising a tubular outer conductor and, within the outerconductor and in coaxial relation to it, an inner conductor, theconductors being separated by a first annular dielectric spacesurrounding the inner conductor, means for connecting the conductors toa coaxial transmission line, said connecting means comprising an outertube connector and, within and coaxial to said outer tube, an innerconnector, the connectors being separated by a second annular dielectricspace surrounding the inner connector, a centrally apertured insulatingpartition interposed between and separating the dielectric spaces, meansextending through the partition aperture in sealing relation from insideto outside and connecting the inner conductor to the inner connector, anannular st ucture disposed across the opening of the housing means,embracing the partition and connecting the outer conductor to the tubeconnector, said structure comprising ring means rigidly attached to thehousing means and to the outer conductor, the ring means having a radialinwardly directed shoulder constituting an inside abutment for thepartition and, outside such shoulder, a circular surface concentric tothe axis of the conductors and engaging the partition to center thelatter in the ring means, the tube connector having a circumferentiallyextending radial surface disposed to bear against and constituting anoutside abutment for the partition, the ring means being formed outsidethe centering surface with means engaging the tube connector andcentering the latter in the ring means, holding means threadedlyengaging one of said ring means and said tube connector and engaging theother thereof interlockingly and for relative rotational movement, saidholding means being actuatable to apply opposite axial forces to thering means and the tube connector to move the radial surface of suchtube connector toward and against the partition progressively squeezingthe latter between such radial surface and the shoulder of the ringmeans, and abutment means coacting between the ring means and the tubeconnector limiting said squeezing and providing axial alignment in theconnection between the tube connector and th outer conductor, the tubeconnector being held in predetermined fixed location axially relative tothe ring means and the outer conductor. 4. In an electrical highfrequency device as claimed in claim 3,

the ring means having a counterbore outwardly of said circular partitioncentering surface, said counterbore providing a cylindrical surfaceengaging the tube connector for relative linear axial sliding movementand constituting said centering means engaging the tube connector. 5. Inan electrical high frequency device as claimed in claim 3,

the holding means including a threaded ring threadedly engaging the ringmeans and, interposed between the threaded ring and the tube connector,split ring means, the split ring means and the tube connector havingengaged radial shoulders constituting said interlocking engagement fortransmitting said opposite forces. 6. In an electrical high frequencydevice as claimed in claim 3,

the ring means having first and second counterbores outwardly of saidcircular partition centering surface, said first counterbore providing acylindrical surface constituting said centering means engaging 9 thetube connector, said second counterbore being formed with threads, andthe holding means including a ring formed with external threads matingwith said counterbore threads in the provision of said threadedengagement.

7. In an electrical high frequency device as claimed in claim 6,

the threaded ring having an internal diameter greater than the diameterof the first counterbore to permit assembly and removal of the threadedring onto and from the tube connector over said outside abutment of thelatter,

and said holding means including split ring means interposed between theexternally threaded ring and the tube connector and adapted to transmitsaid opposite forces.

8. In an electrical high frequency device as claimed in claim 3,

the ring means including fastening ring means secured to the housingmeans and, within and axially movable relative to such fastening ringmeans, mounting ring means,

the outer conductor being fast to said mounting ring means in theprovision of said rigid attachment of the outer conductor to the ringmeans,

said fastening ring means having a through opening larger than theprofile of the coaxial line to permit bodily insertion and removal ofthe latter into and from the housing means through said opening in thefastening'ring means and while the outer conductor is fast to themounting ring means.

9. In an electrical high frequency device as claimed in claim 3,

the opening of the housing means being non circular,

the ring means including fastening ring means secured to the housingmeans and extending through said non circular opening in matingrelation,

and the ring means also including mounting ring means within and axiallymovable in assembly relative to such fastening ring means, the outerconductor being fast to said mounting ring means in the, provision ofsaid rigid attachment of the outer conductor to the ring means.

10. In an electrical high frequency device as claimed in claim 3,

the ring means having a plurality of concentric internal steppeddiameter portions,

a first of said portions being cylindricaland formed with said partitionengaging surface,

a second of said portions also being cylindrical and constituting saidconnector engaging and centering means,

a third of said portions being threaded and threadedly engaged by saidthreaded means,

and said abutment means comprising radial stop means at the juncture ofthe first and second portions.

11. In an electrical high frequency device as claimed in claim 3,

the insulator having an annular radial surface portion engaged by one ofthe abutments and being formed with a circular groove concentric to theaxis of the device and located at one of the margins of and limiting theradial extent of such radial surface.

12. A junction for joining coaxial electrical lines each of whichcomprises an inner and a tubular outer conductor,

said junction comprising an inner connector and, surrounding the innerconnector in coaxial relation and separated therefrom by an annulardielectric space,

an annular outer connector,

the connectors being adapted to extend between and to mechanically andelectrically connect the inner and outer conductors of one such linewith the inner and outer conductors, respectively, of another such line,

an annular insulator disposed in the dielectric space in 1% surroundingrelation to the inner connector and constituting a support for thelatter within the outer connector,

said insulator comprising a body portion defined by surfaces ofrevolution about the longitudinal axis of the device, H the body portionhaving an annular gripping portion of uniform axial section,

one of the connectors including abutment means having confrontingcircular surfaces which are disposed on opposite sides of the grippingportion of the insulator and one of which is inclined with respect tosaid axis,

said one connector having relatively movable parts adapted to beactuated progressively to draw the confronting surfaces toward eachother to engage and squeeze the gripping portion,

the radial extent of the engaged gripping portion constituting only asmall fractional part of the entire radial extent of the insulator body,and the inclination of such one surface providing a dovetail mechanicalinterlock between the one connector and the gripping portion of theinsulator.

13. A coaxial line junction as claimed in claim 12 in which theinsulator includes an integral portion extending axially beyond saidinclined one of the surfaces of the abutment means and also beyond theaxial limits of the gripping portion.

14. A junction for joining coaxial electrical lines each of whichcomprises an inner and a tubular outer conductor,

said junction comprising an inner connector and, surrounding the innerconnector in coaxial relation and separated therefrom by an annulardielectric space, an annular outer connector, the connectors beingadapted to extend between and to mechanically and electrically connectthe inner and outer conductors of one such line with the inner and outerconductors, respectively, of another such line, an annular insulatordisposed in the dielectric space in surrounding relation to the innerconnector and constituting a support for the latter Within the outerconnector, c

said insulator comprising a body portion defined by surfaces ofrevolution about the longitudinal axis of the device,

the body portion having inner and outer peripheries each formed with anannular gripping portion of uniform axial section,

the inner and outer connectors each including abutment means having apair of confronting circular surfaces which are disposed in confiningrelation on opposite sides of the inner and outer gripping portions,respectively,

one surface of each such pair being inclined with respect to said axis,the connectors each comprising parts relatively movable in assembly andadapted to be actuated progressively to draw the abutment surfacestoward each other in effecting a squeezing of the confined grippingportion of the insulator,

the radial extent of each of the squeezed gripping portions constitutingonly a small fractional part of the entire radial extent of theinsulator body,

and the inclination of the abutment surfaces providing dovetailmechanical interlocks between the gripping portions of the insulator andthe connectors respectively squeezing them.

15. In an electrical high frequency coaxial line device of thetype'comprising a tubular outer conductor and, within the outerconductor and in coaxial relation to it, an inner conductor, theconductors being separated by a first annular dielectric spacesurrounding the inner conductor,

means for connecting the conductors to a coaxial transmission line, saidconnecting means comprising an outer tube connector and, within andcoaxial to said outer tube, an inner connector, the connectors beingseparated by a second annular dielectric space surrounding the innerconnector,

outer connecting means electrically connecting the outer conductor tothe tube connector,

a centrally apertured insulating partition within and supported by theouter connecting means and interposed between and separating thedielectric spaces,

inner connecting means extending through the partition aperture andelectrically connecting the inner coductor to the inner connector,

one of said inner and said outer connecting means comprising elementsaxially movable relative to one another and formed with confrontingradial surfaces disposed on opposite sides of and adapted to engage thepartition,

one of said elements being formed with a radial shoulder spaced axiallyfrom its radial surface,

a resilient sealing ring of readily deformable sealing material softerthan the partition embracing said one element and located and heldcaptive between the shoulder and the partition,

and means connecting and adapted to be actuated progressively to drawthe elements together to squeeze the partition between said confrontingsurfaces independently of the sealing ring.

16. In an electrical high frequency coaxial line device of the typecomprising a tubular outer conductor and, within the outer conductor andin coaxial relation to it, an inner conductor, the conductors beingseparated by a first annular dielectric space surrounding the innerconductor,

means for connecting'the conductors to a coaxial transmission line, saidconnecting means comprising an outer tube connector and, within andcoaxial to said outer tube, an inner connector, the connectors beingseparated by a second annular dielectric space surrounding the innerconnector,

outer connecting means electrically connecting the outer conductor tothe tube connector,

a centrally apertured insulating partition Within and supported by theouter connecting means and interposed between and separating thedielectric spaces,

inner connecting means extending through the partition aperture andelectrically connecting the inner coductor to the inner connector,

one of said inner and said outer connecting means comprising a plugelement on one side and a cap element on the other side or" thepartition,

said elements having axially extending complemental guide surfacesengaged one on the other for axial sliding movement and havingconfronting radial surfaces the radial extent of which is only a smallfractional portion of that of the partition, screw means connecting theelements and being actuatable to apply. opposite axial forces to theelements and progressively to squeeze the partition between the radialsurfaces,

abutment means coasting between the elements limiting said squeezing,

the elements being held by said abutment means and said screw means inpredetermined fixed axial rela- "i2 tionship, and one of said connectingmeans including an axially extending member having an end telescopingthe cap and making yielding electrical contact therewith.

17. In an electrical high frequency coaxial line device of the typecomprising a tubular outer conductor and, within the outer conductor andin coaxial relation to it, an inner conductor, the conductors beingseparated by a first annular dielectric space surrounding the innerconductor,

means for connecting the conductors to a coaxial transmission line, saidconnecting means comprising an outer tube connector and, within saidcoaxial to said outer tube, an inner connector, the connectors beingseparated by a second annular dielectric space surrounding the innerconnector,

outer connecting means electrically connecting the outer conductor tothe tube connector,

a centrally apertured insulating partition within and supported by theouter connecting means and interposed between and separating thedielectric spaces,

inner connecting means extending through the partition aperture andelectrically connecting the inner conductor to the inner connector,

one of said inner and said outer connecting means comprising elementsaxially movable relative to one another and formed with confrontingradial surfaces,

one of said elements having a cylindrical guide surface concentric tothe axis of the device,

such one element having its radial surface disposed intermediate thecylindrical surface and the radial surface of the other element,

the partition having integral guide and grip portions, the guide portionengaging the guide surface of such one element and thereby centering thepartition relative to such one element,

and the grip portion being disposed between the radial surfaces of theelements.

18. In a device as claimed in claim 17 the partition being formed withcoaxial cylindrical peripheral surfaces of different diameters,

one such peripheral surface delineating the guide portion and being inengagement with the guide surface and the other such peripheral surfacedelineating the grip portion.

References Cited in the file of this patent UNITED STATES PATENTS2,449,073 Iohannesen Sept. 14, 1948 2,513,080 Burtt June 27, 19502,536,802 Fehr Jan. 2, 1951 2,552,707 Bird May 15, 1951 2,556,642 BirdJune 12, 1951 2,663,753 Bird Dec. 22, 1953 2,822,418 Dinnick Feb. 4,1958 2,882,509 Archer et al Apr. 14, 1959 2,904,619 Forney Sept. 15,1959 FOREIGN PATENTS 839,587 Franc Ian. 4, 1939 840,649 France Jan. 23,1939 879,562 Germany June 15, 1953 879,563 Germany June 15, 1953 v sc I

1. A JUNCTION FOR JOINING COAXIAL LINE SECTIONS EACH OF WHICH COMPRISESAN INNER AND A TUBULAR OUTER CONDUCTOR, SAID JUNCTION COMPRISING ANANNULAR OUTER CONNECTOR FOR EXTENDING BETWEEN AND ELECTRICALLYCONNECTING THE OUTER CONDUCTORS OF THE LINE SECTIONS, AN INNER CONNECTORFOR EXTENDING BETWEEN AND ELECTRICALLY CONNECTING THE INNER CONDUCTORSOF THE LINE SECTIONS, INSULATING MEANS SURROUNDING THE INNER CONNECTORAND SUPPORTING IT COAXIALLY WITHIN THE OUTER CONNECTOR, AND MEANS HAVINGA SURFACE INCLINED TO THE AXIS OF THE CONNECTORS PROVIDING A DOVETAILANNULAR INTERLOCK BETWEEN THE INSULATING MEANS AND ONE OF THECONNECTORS, SAID INCLINED SURFACE ENGAGING THE INSULATING MEANS OVER ARELATIVELY SMALL FRACTIONAL PORTION ONLY OF THE RADIAL EXTENT OF THEINSULATING MEANS.